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Extraction of rare earth oxides from discarded compact fluorescent lamps
摘要： Discarded CFL samples are evaluated as a potential source of REEs (Y, Eu, Ce, Tb). The phosphors powder obtained from mechanical separation contains 31% rare earth values. The quantitative XRD analysis of phosphor sample yielded 39.9% red (YOX: Y1.90Eu0.10O3), 14.6% green (CAT: Al11Ce0.67MgO19Tb0.33), and 21.4% blue (BAM: Al10.09Ba0.96Mg0.91O17: Eu2+) phosphor along with 14.1% silica. Planetary ball milling was found promising in the liberation of REEs from given phosphor sample. A short milling of 20–30 min and 3–4 M acid concentration was found adequate for optimal recovery (> 90%) of REEs. Calcination of the precipitates resulted in the formation of REO with Y-Eu purity of > 98% and > 90% recovery rate. Eu, Y phase dissolution behavior was found completely different than Ce, Tb phase due to inert nature of Al11Ce0.67MgO19Tb0.33 till 120 min milling and 6 M acid concentration in leaching. Excessive milling promotes overall dissolution along with impurities dissolution and which further restrict the precipitation process. Based on the complete material balance 13 g of a mixed oxide of Y and Eu can be obtained from 100 units of CFLs.
关键词： Discarded CFL,Phosphor,Rare earth elements,Leaching,Mechanical milling
更新于2025-11-21 11:18:25
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Silver nanoflowers-enhanced Tb(III)/La(III) co-luminescence for the sensitive detection of dopamine
摘要： A sensitive fluorescent analytical method for the detection of dopamine (DA) was developed based on surface-enhanced Tb(III)/La(III) co-luminescence using silver nanoflowers (AgNFs). Anisotropic AgNFs show strong surface-enhanced fluorescence effect owing to the abundant sharp tips. Tb(III)/La(III)-DA complexes mainly bind to the sharp tips of AgNFs and thus shorten the distance between the complexes. The shortened distance gives rise to obvious surface-enhanced Tb(III)/La(III) co-luminescence effect. In this work, AgNFs offer many superior properties, such as enhanced intrinsic green fluorescence of Tb(III) (λex/λem = 310/546 nm), increased fluorescence lifetime, and improved energy transfer efficiency. Under the optimum conditions, the fluorescence intensity is linearly correlated with the concentration of DA in the range of 0.80–10 nM (R2 = 0.9970), and the detection limit is 0.34 nM (S/N = 3). The fluorescent nanoprobe was successfully applied to the determination of DA in human serum samples with recoveries ranging from 99.1 to 102.6%.
关键词： Co-luminescence,Anisotropic nanoparticles,Surface-enhanced fluorescence,Rare earth elements,Dopamine,Silver nanoflowers
更新于2025-09-23 15:22:29
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Luminescent nanomaterials for droplet tracking in a microfluidic trapping array
摘要： The use of high-throughput multiplexed screening platforms has attracted significant interest in the field of on-site disease detection and diagnostics for their capability to simultaneously interrogate single-cell responses across different populations. However, many of the current approaches are limited by the spectral overlap between tracking materials (e.g., organic dyes) and commonly used fluorophores/biochemical stains, thus restraining their applications in multiplexed studies. This work demonstrates that the downconversion emission spectra offered by rare earth (RE)-doped β-hexagonal NaYF4 nanoparticles (NPs) can be exploited to address this spectral overlap issue. Compared to organic dyes and other tracking materials where the excitation and emission is separated by tens of nanometers, RE elements have a large gap between excitation and emission which results in their spectral independence from the organic dyes. As a proof of concept, two differently doped NaYF4 NPs (europium: Eu3+, and terbium: Tb3+) were employed on a fluorescent microscopy-based droplet microfluidic trapping array to test their feasibility as spectrally independent droplet trackers. The luminescence tracking properties of Eu3+-doped (red emission) and Tb3+-doped (green emission) NPs were successfully characterized by co-encapsulating with genetically modified cancer cell lines expressing green or red fluorescent proteins (GFP and RFP) in addition to a mixed population of live and dead cells stained with ethidium homodimer. Detailed quantification of the luminescent and fluorescent signals was performed to confirm no overlap between each of the NPs and between NPs and cells. Thus, the spectral independence of Eu3+-doped and Tb3+-doped NPs with each other and with common fluorophores highlights the potential application of this novel technique in multiplexed systems, where many such luminescent NPs (other doped and co-doped NPs) can be used to simultaneously track different input conditions on the same platform.
关键词： Rare earth elements,Single-cell analysis,Nanoparticles,Microfluidics,high-throughput screening
更新于2025-09-23 15:21:21
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Leaching Kinetics of Yttrium and Europium Oxides from Waste Phosphor Powder
摘要： Phosphor powder sample was characterized, and the leaching kinetics of yttrium, and europium in hydrochloric acid were investigated. Under optimized leaching conditions, 98% Y and 97% Eu were extracted, and a reaction curve was generated using the percentage of extraction as a function of time and temperature. Based on R2 values, shrinking spherical particle and shrinking core model were not applicable. SEM analysis also con?rmed shrinking core behavior was not applicable due to the lack of core–shells in the leach residue. The kinetic data were best ?tted by a logarithmic rate expression of the empirical model. Activation energy was calculated to be 77.49 kJ/mol for Y and 72.75 kJ/mol for Eu in the temperature range of 298–343 K.
关键词： Leaching,Phosphor powder,Rare earth elements,Waste ?uorescent lamp,Kinetics
更新于2025-09-23 15:21:01
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Highly selective antenna effect of graphene quantum dots (GQDs): A new fluorescent sensitizer for rare earth element terbium in aqueous media
摘要： This study focused on the fluorescence antenna-sensitizing effect of graphene quantum dots (GQDs) in a case on the detection of terbium ions. A simple one-step chemical oxidation method was applied for the preparation of GQDs starting from the regular multilayer graphene oxide (GO) via the refluxing in a concentrated mixture of strong acids. The as-prepared GQD were further evaluated as a fluorescent sensitizer to the terbium ion. An expanded in-deep mechanism study on the fluorescence phenomena during the interaction of the as-prepared GQDs and REEs was made. The highly selective antenna effect of GQD on one of REEs’ aqueous media, which was terbium (III), was identified. The excited terbium ion emitted its long-living fluorescence based on its own characteristic line-typed f-f transition, contrasting to a undetectable fluorescence in a very poor quantum yield in its aqueous solution induced by water collisions. This study, in the first place, identified the significant sensitization effect of the as-prepared GQD on the terbium ion in a high selectivity in aqueous media. The detectable linear range and the detection limit of the terbium ion was 0-30×10-6 mol L-1 (R2=0.9960) of 0.3 × 10-6 mol L-1, respectively. The excitation wavelength and the optimal fluorescence wavelength were 230 nm 546 nm, respectively. Further material characterizations, involving XPS, FTIR, Raman and the Zeta potential, verified the important participation of carboxyl function groups on the as-prepared GQD.
关键词： Fluorescence,Grapheme quantum dots,Rare earth elements,Terbium,Antenna-sensitizing effect
更新于2025-09-23 15:19:57
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Development of a Thulium Fiber Laser for an Atomic Spectroscopy Experiment
摘要： A convenient thulium ?ber laser source is described with 3 W of output power operating at a wavelength of 2059 nm with a slope e?ciency of 49% with respect to input pump power and 60% with respect to absorbed pump power. The laser was applied in an atomic helium spectroscopy experiment to quench 3He (2058.63 nm) and 4He (2058.69 nm) meta-stable singlets (21S0), allowing for further investigation of the helium ?ne structure. The customized laser e?ectively eliminates the singlet counts to well below a background level (1%). A simpli?ed analysis describes the basic laser performance with ?tted constants in reasonable agreement with previous work.
关键词： fiber,thulium fiber laser,laser,spectroscopy,fiber laser,rare-earth elements,optics,thulium
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Light Shaping for Reconfigurable Microscale Temperature Control
摘要： Recycling rare-earth elements (REEs) from Nd-Fe-B magnet waste is an important step towards building a sustainable REE supply chain. In this study, two different processes were systematically investigated and compared. In the leaching stage, the effect of increasing H2SO4 or HCl concentrations were studied and it was determined that, although both can successfully promote REEs, B, Fe and Co leaching, HCl solutions extracted a wider range of metals. After leaching, the oxalate and double-sulfate precipitation methods were utilized to separate REEs from either HCl or H2SO4 leachates. Results suggest that, although > 99% REEs precipitation rates could be achieved with oxalate, the purity of REE-containing products is significantly affected by impurities like Fe and Co. In contrast, REE double-sulfate precipitation resulted in a product purity of > 99%; however, high levels of Na2SO4 (8 times the stoichiometric amount) were needed to achieve > 98% of REE precipitation.
关键词： rare-earth elements,precipitation,leaching,Nd-Fe-B magnets,recycling
更新于2025-09-12 10:27:22
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Rare-earth element doping in glass frit for improved performance in silicon solar cells
摘要： Glass frit plays an important role in the silver paste for silicon solar cells. In this work, we prepare glass frit doped with different rare-earth elements (Y, La, Sm, Er) and study how the doping element affects the performance of the solar cells. Solar cells with La-doped and Sm-doped glass frits show average conversion efficiencies higher than 17.5%, while solar cells with Y-doped or Er-doped frit show lower efficiencies. By analyzing the Raman spectra of the rare-earth doped glass frits, we find that the average coordination number of Te–O (NTe(cid:1)O) in the glass can be tuned by the rare-earth dopant. La or Sm doping leads to a moderate value of NTe(cid:1)O, which is believed to achieve a glass formation ability that optimizes the structure of the Ag–Si interface of the cell for the best performance.
关键词： rare-earth elements,glass frit,Solar cells,Raman spectra
更新于2025-09-12 10:27:22
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Tuning the optical properties of ZnO:Cd by doping La and Y
摘要： Zinc oxide doped with Cadmium and rare earth elements synthesized by solgel auto combustion route is reported in this work. The studies have been carried out to analyze the structural, morphological and optical properties of Cd doped ZnO and rare earth doped ZnCdO. The XRD analysis reveals that the addition of rare earth impurity decreases the particle size of ZnCdO. La doped ZnCdO has the least particle size among the samples of ZnCdO and rare earth doped ZnCdO. The morphological changes due to the addition of rare earth impurities have been found. Samples of La doped ZnCdO shows a pillar like morphology. The hexagonal structures are prominently seen in the SEM micrographs of the samples of ZnCdO. The UV-Visible spectral analyses show that the bandgap reduces when ZnCdO is doped with the rare earth impurities. The photoluminescence spectra show the broad spectrum in visible region exhibited by ZnO and a scanty UV emission. The UV emission of rare earth doped samples decreases due to the destruction in the crystal structure. The rare earth doped ZnCdO shows a small peak in green emission that decreases when rare earth impurities are doped. There is a uniform spectral response other than a small Gaussian like green peak. The overall analyses show that the samples can be used in optoelectronic applications to work in the visible region.
关键词： rare earth elements,structural properties,optical properties,UV-Visible spectral analyses,Cadmium,SEM micrographs,photoluminescence spectra,XRD analysis,Zinc oxide,solgel auto combustion,morphological properties
更新于2025-09-09 09:28:46
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Electroluminescence of intrashell transitions in Eu doped single ZnO nanowires
摘要： Tunable nanoscale light emitters are essential to accomplish future multifunctional optoelectronic nano-devices. Here, we present an approach for achieving red electroluminescence from single ZnO nanowires implanted with Europium ions. The electroluminescence is emitted mainly from the end facets of ZnO nanowires at room temperature under the application of an AC voltage. The corresponding electroluminescence spectrum is attributed to the radiative intrashell transitions of the Eu ions, while contributions from near band edge or deep level emission of the ZnO remain absent. The total intensity of the electroluminescence is linearly proportional to the length of the nanowires, whereas there is no clear correlation with other morphology factors of the nanowire based device such as the diameter. Furthermore, the underlying excitation mechanism of the electroluminescence is proposed as direct-impact excitation of Eu ions by hot electrons in the ZnO nanowires.
关键词： electroluminescence,Zinc oxide (ZnO),Europium (Eu),nanowires,rare earth elements,ion beam doping
更新于2025-09-09 09:28:46